1. Field of the Invention
This invention relates to mechanism for forming a stack of flat articles and for subsequently handling such article stack.
2. Problem
In stacking flat articles such as frozen pancakes, frozen French toast slices, frozen waffles or hamburger patties, for example, for packaging or processing in a stack, it is desirable to stack such articles quickly and to handle the formed stacks expeditiously by mechanism which is of simple construction and which can be operated efficiently.
3. Prior Art
While the Burgis et al. U.S. Pat. No. 4,034,846, issued July 12, 1977, shows apparatus for stacking flat articles, such apparatus requires that the articles be of magnetic material such as automotive baffles or hydropans, as stated at column 2, line 10, and column 3, line 15. The stacking mechanism of this patent does not provide for continual movement of the conveyors for moving the articles into the stacking mechanism or out of the stacking mechanism but requires that both the infeed conveyor and the outfeed conveyor be stopped intermittently while carrying a considerable number of articles.
The stacking mechanism shown in the Feldkamper U.S. Pat. No. 3,683,758, issued Aug. 15, 1972, shows mechanism for stacking flattened paper bags or sacks (column 2, lines 29 and 30, and column 3, lines 64 and 65) supplied to the stacking equipment in an overlapping or scaled or shingled formation (column 5, lines 14 to 17, and FIGS. 1,2 and 4). The supply conveyor is driven at a higher speed to pull a counted stack of bags from the preceding bags (column 7, lines 25 to 33) and is driven at a lower speed to move the counted bags into the stacking station (column 7, lines 40 to 42 and 49 to 62). The bags are evened in the stack by striking a wall (column 7, lines 60 to 62) which wall is swung upward out of the way of the stack when the stack is to be removed from the stacking magazine (column 5, line 61, to column 6, line 2 ). The stack of bags is accumulated on the conveyor belt (column 5, lines 60 and 61), as indicated in FIG. 1, the feed conveyor essentially feeds a shingled stack of flat bags into and against a wall of a stacking magazine which evens up the bags in the stack.
The Coakley U.S. Pat. No. 2,919,789, issued Jan. 5, 1960, shows an apparatus for stacking paper bag tubes that again are arranged initially in shingle fashion, as shown in FIGS. 2 and 3, and again are stacked on the upper stretch 7a of a belt 7. The shingled stack is fed by belt 5a onto the belt 7 and, after the stack has accumulated on this belt, its movement is started to feed the stack onto a table, as described at column 3, lines 38 to 45.
In Richards et al. U.S. Pat. No. 3,952,478, issued Apr. 27, 1976, and Sandberg et al. U.S. Pat. No. 4,137,604, issued Feb. 6, 1979, stacks of flat articles again are accumulated on a belt while it is stopped and, after the stack has accumulated, the belt is started again. The mechanism shown in these patents for placing the articles on the belts is different from that disclosed in the other patents discussed above.
The Lekan U.S. Pat. No. 3,675,387, issued July 11, 1972, and the London et al. U.S. Pat. No. 3,810,554, issued May 14, 1974, show stacking mechanism for forming stacks on stationary surfaces and no mechanism is shown for removing the stacks from such surfaces. The stacking mechanism of the Lekan patent is similar to the stacking mechanism shown in the Richards et al. U.S. Pat. No. 3,952,478 discussed above.